Meaning

noun a large smooth mass of rock detached from its place of origin

noun a town in north central Colorado; Rocky Mountains resort center and university town

originFrom late Middle English bulder, short for Middle English bulder ston (“a stone that's been worn into a round shape, boulder, cobblestone”), possibly from Old Swedish *buldersten, itself possibly from Old Swedish bulder (“rumble, noise”) + sten (“stone”); whence dialectal Swedish bullersten (“large stone in a stream, causing water to roar around it”). The first element may alternatively be allied…

Etymology from Wiktionary, CC BY-SA 3.0